| 摘要 |
PURPOSE:To provide a cutting tip made of the above-captioned material for cutting cemented hardened steel or the like and having an excellent breakage resisting property by constituting a specified volume % or more of cubic system boron nitride of elongated cubic system boron nitride having a specified or less grain size. CONSTITUTION:This cutting tip contains a kind or at least two kinds of 20-60vol% of TiC, TiN, TiB2, WC, Al2O3 and AlN and solid solution of at least two kinds thereof as bonding phase components and the rest composed of cubic system boron nitride(hereinafter called CBN) as a dispersed phase component and CBN group sintered material having inevitable impurities. In such cutting tip, 50 or more vol % of CBN as the dispersed phase component is constituted of the elongated CBN of 10mum or less average grain size, preferably that of ratio 1.5-8 of the longer axis to shorter axis. Further, the rate of the elongated CBN is determined to be 50vol% or more. |
